1. Technical Field
The present invention generally relates to tire tag devices used in pneumatic tires to monitor conditions of the pneumatic tires. More particularly, the present invention relates to a method of encapsulating a tire tag wherein the antenna is separate and spaced from the monitoring package. Specifically, the present invention relates to a method of encapsulating an electronic tire tag wherein the position of the antenna is held in place during the encapsulation process so that the orientation of the antenna is known after the encapsulation process.
2. Background Information
Tire tags used to monitor engineering conditions of pneumatic tires are becoming increasingly desired in the tire art. Tire tags are being used to monitor temperature, pressure, and other engineering conditions inside pneumatic tires while the tires are in operation on vehicles. The most desirable type of tire tag transmits data out of the pneumatic tire with radio waves so that a direct external physical attachment between a reader and the tire is not needed to gather data.
Tire tags that transmit data out of the tire generally include a monitoring package that includes sensors, memory, a controller, a transmitter, and a receiver that are used to gather, store, receive, and transmit data and instructions. The tire tag also includes a power source such as a battery. These tire tags also include an antenna used to create the outgoing signals and receive the incoming signals.
Tire tag antennae have been located in a variety of positions with respect to the monitoring package in the prior art. Antennae have been connected directly to the circuit board, mounted on the tire rim, mounted in the tire, extending away from the monitoring package into the cavity of the tire, and mounted in a patch with connections to the monitoring package. One problem in the art is maintaining adequate connections between the monitoring package and the antenna. Maintaining the connections is difficult because a tire is not a stable mounting surface. The bending and flexing of the tire body stresses the connections between the antenna and the monitoring package. The art thus desires a mounting configuration for the antenna wherein the connections between the antenna and the monitoring package are protected from the flexing forces of the pneumatic tire.
The art has also recognized that the position of the antenna with respect to the tire can be critical for obtaining strong signals into and out of the pneumatic tire. The mounting configuration of the antenna thus must provide a predictable position for the antenna when the mounting of the antenna is complete. In other words, the process of mounting the antenna must result in a predictable antenna position with respect to the monitoring package so that the antenna may be correctly mounted in the pneumatic tire for strong transmission signals.
In view of the foregoing, the present invention provides a method for encapsulating a tire tag wherein the antenna and monitoring package are encapsulated together so that the connection between the antenna and the monitoring package is captured within a rigid encapsulation material that prevents the connection between the antenna and the monitoring package from breaking when the tire tag is used in a dynamic pneumatic tire environment.
The invention provides devices and configurations for holding the antenna in a fixed position with respect to the monitoring package or encapsulation mold so that the final position of the antenna may be readily determined after the encapsulation process is complete.
In general, the invention provides a method wherein the antenna is mounted to the encapsulation mold in a known position, the remaining elements of the monitoring package are assembled into the encapsulation mold, and the encapsulation material is added to the mold to encapsulate the elements of the tire tag and to fix the positions of the elements with respect to each other.
The invention also provides different types of connections between the antenna and the monitoring package that ensure a consistent, reliable connection between the antenna and the monitoring package.
In one embodiment of the invention, the antenna blades are directly connected to the monitoring package with wires that are soldered to each element. In another embodiment, spring-loaded connecting pins extend between the monitoring package and the blades to create a constant force between the antenna blades and the spring loaded connecting pins to ensure a reliable connection.
The invention also provides a variety of different locations for the antenna within, outside of, and embedded within the encapsulation mold. In addition, the invention provides a variety of arrangements to hold the antenna with respect to the encapsulation mold while the encapsulation mold is being filled with the encapsulation material.